Process of producing glutamic acid compounds



Patented Feb. 26, 1935 PROCESS OF PRODUCING GLUTAHIG ACID COMPOUNDS Edward Bartow and Raymond L. Albroolr, Iowa City, Iowa, assignors to A. E. Staley Manufacing Company, Decatur, 111., a corporation of Delaware No Drawing. Application m 9, 1932, Serial No. 621,750

4 Claims.

This invention relates to the production of glutamic acid compounds and has for-its principal object the provision oi. an economical and practical process for producing glutamic acid 5 compounds irom corn gluten as ordinarily derived in the manufacture of starch from Indian corn. I

.Glutamic acid may be extracted from corn gluten by digesting the gluten with hydrochloric acid. Such reaction, however, produces a .considerable amount of char and decomposed or ganic matter which is difiicult to remove from the produced glutamic acid, after digestion is completed.

This invention contemplates the separation of the prolamin orzein from the gluten and digestion of the zein or prolamin to provide the glutamic acid and/or glutamic acid compounds. Experiment has demonstrated that where the prolamin or zein (as contradistinguished from raw corn gluten) is digested char and decomposed solid matter need not be produced and a.

resultant mother liquid is obtainable from which I the glutamic acid hydrochloride crystallizes easily and completely.

The zein or prolamin may be extracted from the gluten in accordance with the process described in the pending application for United States letters Patent Serial No. 558,840 filed August 22, 1931 by Donald William Hansen, which consists generally of extraction of the prolamin or zein Irom gluten press cake by the useotasolventconslstingotamixtureofan alcohol and water. The .alcohol conveniently may be either ethyl, methyl or propyl alcohol, or a mixture 01 these alcohols. Ordinarily, the. ratiosbyvolumeor alcohol and waterwillbe in t the general neighborhood of 70% or 80% alcohol and 30% or water. In production, abulkingmat'erial, suchasco'rnhullaismixed with the alcoholic solution and heated in a suitable extractor to aboutlm F. The gluten press cake, containing about 50% water, is slowlyaddedwhilethemassisconstantbstirred. Whensumcientglutenhasbeenaddedtobring the aein concentration up to approximately 6%,

thestirringisstoppedandatterashortperiod otrestthesolventisdrained away. The'zein solutionisfilteredandevaporatedtoathin= syrupy.

A 70% alcohol solventis used and the remaining solvent'will'contain about 50% water. Oncoolingtheaeinprecipitatesasavlscousliquid containing about 50% solids.2 5% alcoholand% water. The supernatantliquidisremovedandanequalweightot substantially 95% alcohol is added and thoroughly mixed with the zein. This mixture provides a paste of approximately 25% solids in an 83% alcohol solvent.

The zein is or may be precipitated from the 5 first alcohol solution into a relatively large body of water and passing the residual gummy mass through rollers and drying at a low temperature, preferably under a vacuum, 1

The glutamic acid hydrochloride may be pre- 10 ,pared in accordance with the present invention by treating this zein with hydrochloric acid. A typical example of such treatment consists of treating 150 grams of'prolamin paste with 250 cc. of hydrochloric acid in a 1 liter flask. The 15 flask is preferably connected with a reflux condenser andheated to hailing from 8-12 hours. The resultant mass while still warm is preferably decolorized by 25 grams of vegetable -charcoal and filtered. The, resulting filtrate is con- 20 centrated under vacuum until crystals of glutamic acid hydrochloride begin to separate out. The filtrate is then allowed to stand until crystallization is complete and the crystals are then removed and dried.

The crystalline glutamic acid hydrochloride may thereafter be converted into desired glutamic acid compounds, as for example it may be converted into monosodium glutamate by neutralizing the glutamic acid. hydrochloride with sodium carbonate' This may be accomplished by dissolving the sodium carbonate in water and adding glutamic acid hydrochloride crystals. In the resulting reaction both sodium chloride and sodium glutamate are formed and evaporation will accomplish, first, crystallization of the sodium chloride which may be filtered out, and thereafter further concentration will produce crystalline monosodium glutamate.

Where zein or prolamin' paste is employed no 40 charring oi the materials occurs and the time required for the completion of the digestion is less than where production of glutamic acid compound is attempted from corn gluten.

The practice o1 the process also results in increased yield, anddifiiculty ofseparation is Ina-- terlally reduced.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the steps and'their order of accomplishment of the process described without departing from the spirit and scope of the invention or sacrificing all 01' its material advantages, the process here- I inbeiore described being merely a preferred embodiment thereof.

We claim: I

1. The process of producing glutamic acid compounds, which comprises the steps of extracting zein from gluten press cake by use of a solvent consisting of a mixture of an alcohol and water, and digesting the zein thus produced with hydrochloric acid without submitting the zein to a purification treatment prior to such digestion.

2. A process of producing glutamic acid compounds, which comprises the steps of extracting'zein from gluten press cake by the use of a solvent consisting of a mixture of an alcohol and water, and digesting the zein thus produced with hydrochloric acid to form glutamic acid hydrochloride in crystals, said digestion being effected without submitting the zein to a purification treatment prior thereto.

3. A process of producing glutamic acid compounds which comprises the steps of extracting zein from gluten press cake by the use of a solvent consisting of a mixture of an alcohol and water to furnish an extract in the form of a paste consisting of about 25 per cent. of solid zein and '25 per cent. of solvent, and heating said paste in hydrochloric acid, decolorizing the condensate produced by the heating with charcoal, filtering the decolorized condensate, and concentrating the filtrate under vacuum.

4. A process of producing glutamic acid compounds, which comprises the steps of extracting zein' from gluten press cake by the use of a solvent consisting of a mixture of an alcohol and water, converting the zein in the resulting solution into the form of a dry powder, digesting said powder with hydrochloric acid in a reflux condenser, said digestion being efiected without submitting the zein to a purification treatment prior thereto, decolorizing the condensate by charcoal, filtering the decolorized condensate and concentrating the filtrate until crystals of glutamic acid hydrochloride separate out.

EDWARD BARTOW. RAYMIOND L. ALBROOK- 

